1. Technical Field of the Invention
This invention pertains to client/server systems. More particularly, it relates to enabling graphical applications to run on a traditionally text based host.
2. Background Art
Many new software applications developed for the Internet are Java based, because Java is a prime operating system (OS) portability facilitator. Theoretically, a Java-based application can run on any Operating System unchanged, be it Windows95, Linux, OS/2, VM, etc. It also has the advantage of being able to tie into the Graphical User Interface (GUI) support of a host through an Abstract Window Toolkit (AWT), which is a standardized OS interface for application graphics support. (AWT is a product of Sun Microsystems.)
Having GUI support enables the blending together of graphics and text from a variety of sources into one seamless screen or “panel”, a highly desired attribute for any OS or application.
Unfortunately, many legacy application environments don't conveniently lend themselves to a GUI interface. Most of these legacy machines have added additional support consistent with the connectionless, stateless, http class of web servers. These Web based applications have to incorporate some method of state maintenance in order to mimmick a traditional connection and state oriented legacy programming model. These models are typically mainframe interactive. Many legacy applications can't really blend graphics and text very well—that is, until recent technology innovations have afforded some relief. For example, through use of Java applications great strides have been made in blending graphics and text.
IBM's AS/400 system legacy programming model has a text-only “green screen” interface (so named after the default color of text on the screen). This presents a problem porting popular Java applications to the AS/400, since many such applications require GUI support. Since the AS/400 system is a business computer, this means many businesses cannot easily migrate their legacy applications to their customers with a GUI interface. For example, suppose company ABC, Inc. offers customers terminal access to its AS/400 system and all the business applications installed on it, charging an hourly rate for connect time to use these applications. Customers connect to the AS/400 using a Telnet Client and get a text-only terminal emulator, at best. They cannot take advantage of GUI enabled Java applications that may be installed or ported over from other platforms.
IBM solved this problem on the AS/400 by adding Remote Abstract Window Toolkit support (RAWT). With Remote AWT, Java AWT graphical programs can be executed on a AS/400 system while remotely displaying the graphics.
The use of Remote AWT requires that Transmission Control Protocol/Internet Protocol (TCP/IP) be set up, and Sun Microsystems, Inc., Java Developer's Kit (JDK) 1.1.x installed on both the server AS/400 and the remote display. Any graphics-capable hardware, including IBM Network Station, can be used as a remote display for Remote AWT as long as it includes:
1) Graphics-capable hardware that runs Windows 95, Windows NT 4.0, Windows ME, Windows 2000, IBM Operating System/2 (OS/2), Sun Solar, Sun Solaris or AIX.
2) Configured hardware to access AS/400 with TCP/IP.
3) Java Developer's Kit 1.1.x (JDK 1.1.6 or later is recommended.)
AWT refers to Abstract Window Toolkit. The AWT is part of the Java Foundation Classes (JFC)—the standard API for providing graphical user interfaces (GUIs) for Java programs. This is a platform-independent windowing, graphics and user interface toolkit. With the Remote Abstract Window Toolkit (RAWT), a Java AWT graphical program can run on the AS/400 (a text-only platform) and display the graphics remotely. To use Remote AWT, the Transmission Control Protocol/Internet Protocol (TCP/IP) is set up, and Sun Microsystems, Inc., Java Developer's Kit (JDK) 1.1.x installed on the AS/400 and remote display.
As an example, this support is used to supply the interface for Operations Navigator, a remote configuration tool that ships free with every AS/400 as part of the 5769-XE1 Licensed Program Product, and allows AS/400 System Administrators to configure an AS/400 using a remote Windows 95/NT/2000 platform.
There are also Java-based terminal emulator clients, such as IBM's Host-On-Demand product. These are truly GUI clients, but they connect to the traditional TCP/IP Telnet Server, which primarily supports “green screen” applications. IBM's Network Station is similar, in that it is also a GUI capable client and can exploit tunneling of graphics from the integrated file system (IFS) on the AS/400, but this is not using Java virtual machine (JVM) capabilities on the AS/400. Further, Host-On-Demand must do many kinds of datastream conversions to work with a variety of Telnet Servers. For example, to communicate with OS/400 (AS/400), the Java client must convert 5250 datastreams into something the host GUI understands, in order for it to display on the client Operating System. Likewise, for VM systems (S/390) 3270 datastreams must be converted to host GUI. Replicating this across a few more platforms results in considerable code expansion in a Java-based client, if it is expected to support more than one platform.
Host-On-Demand supports “servlets”, which are supposed to be Java applets that run on a server machine. But, by requiring a Host-On-Demand client, servlets cannot be exploited on Thin Clients, such as Network Stations.
The problem with using Operations Navigator to run Java applications is that it is a custom application, and requires a custom server on the AS/400 system to run the Remote AWT. There is no Internet standard or protocol by which graphical clients can connect to the AS/400 system and run the Remote AWT (and by extension, a Java application).
It is, therefore, an object of the invention to provide an improved system and method for enabling graphics enabled applications to run on a text based host.
It is a further object of the invention to provide a system and method whereby an AS/400 host can enable standard Telnet Clients to connect and be able to receive output from Java graphics applications.
It is a further object of the invention to provide a system and method for graphics enabled application platform independence for workstations by supporting a variety of clients and hardware.
It is a further object of the invention to provide an improved system and method for exploiting a Java virtual machine on a text based host system to run both text based and remote graphics applications, such as Java and X Windows applications.
It is a further object of the invention to provide a system and method for enhancing the ability of a text based host system to perform work management, including authentication, NLS, and job routing, for many clients at once.
It is a further object of the invention to provide an improved system and method for centralizing applications and support for applications.
It is a further object of the invention to provide an improved system and method for centralizing of backup/recovery processes.
It is a further object of the invention to provide an improved system and method for centralizing upgrades/fixes, such that such upgrades and fixes need be done only one time, not once for each workstation.
It is a further object of the invention to provide a system and method for comprising a single source for consulting, leasing, and marketing text based and graphical applications.
It is a further object of the invention to provide an system and method for supporting thin clients, such as network stations, by offloading CPU cycles workstations to a central mainframe.
It is a further object of the invention to provide an improved system and method for using existing terminal emulators which requires no new development and exploits existing standards, including Internet RFC'S.